1. Field of the Invention
The present invention relates to a self-light-emitting device in which an EL element structured by a light emitting organic material, in which EL (electroluminescence) is obtained, is sandwiched between an anode and a cathode, and to a method of manufacturing electronic equipment having the self-light-emitting device as a display portion (display or display monitor). Note that the above stated self-light-emitting device is also referred to as an OLED (organic light emitting diode).
2. Description of the Related Art
The development of display devices (also referred to as a self-light-emitting device and an EL display device) using an EL element as a self-light-emitting element which utilizes the EL phenomenon of light emitting organic material has been advancing in recent years. The self-light-emitting device emits light by itself, and is looked upon as promising as a display portion of electronic equipment because a back light, such as that of a liquid crystal display device, is unnecessary, and in addition, it has a wide angle of view.
Two types of self-light-emitting devices exist, a passive type (a simple matrix type) and an active type (an active matrix type), and development of both types is brisk. In particular, active matrix type self-light-emitting devices are currently in the spotlight. Further, low molecular weight organic EL materials and high molecular weight (polymer) organic EL materials are being researched as organic EL materials which become an EL layer, which can be said of as the heart of an EL element, but the polymer organic EL materials are being focused upon, more than the low molecular weight EL materials, due to their ease of handling and thermal resistance.
However, when applying a solution in which a polymer organic EL material is dissolved in a solvent, problems such as: liquid cut-off of a discharge portion due to the viscosity of the solution or to surface tension in the discharge portion; and liquid clogging in the discharge portion can develop. Note that, throughout this specification, an EL layer application liquid in which an organic EL material is dissolved in a solvent is referred to as an application liquid. Further, the application liquid include not only applying a solution in which a polymer organic EL material is dissolved in a solvent but also applying a solution in which a polymer organic EL material and monomer organic EL material dissolved together in a solvent.
In addition, there are organic EL materials which emit phosphorescence or fluorescence, where phosphorescence is triplet-based light emission and fluorescence is singlet-based light emission. For the self-light-emitting device of the present invention, it is possible to use either organic EL materials which emits phosphorescence or fluorescence.
Further, it is possible to control the film thickness of the application liquid by applying it with an application method which uses a spinner. However, if a spin application method is used, it becomes sandwiched with processes of wet etching, which is not preferable with respect to an organic EL material.